The Importance of Having the Right Type of Fire Extinguisher

A fire extinguisher can be a valuable tool in keeping a small fire from spreading and potentially putting people or property at risk. Fires can occur in any environment, and they happen to businesses of all sizes. Whether you work with cooking grease, electrical wires or hazardous materials, you need to be prepared for the possibility of fire in your workplace. In addition to having an evacuation plan, making sure you have the right type of fire extinguisher is essential.

There are four essential elements needed for a fire to grow: heat, oxygen and fuel. Fire extinguishers remove one of these, or put a barrier between the fire and the oxygen supply, to stop the chain reaction that leads to flames. Water can be used to extinguish a fire, but it is ineffective against many types of commercial or industrial fuels. That’s why you need to have a variety of fire extinguishers in your workplace to tackle different types of fires.

Class A extinguishers are designed to handle ordinary combustibles such as paper, wood, cloth and trash. Class B extinguishers handle flammable liquids, such as grease and gasoline. Class C extinguishers can be used on energized electrical equipment or combustible metals such as iron and steel.

A foam fire extinguisher forms an air-excluding soapy blanket that smothers the flames. It works through the chemical process of saponification (a base reacting with a fat to form a soap) and by cooling the burning oil below its ignition temperature. Class D fire extinguishers contain a conductive metal salt, such as magnesium chloride or sodium bromide, that smothers the fire by conducting electricity through the burning fuel and inhibiting the chemical reactions involved in combustion.

Dry powder fire extinguishers (classes ABC) can be used to smother and disperse hot burning combustibles. They are commonly rated A:B:C, with the number preceding the “A” indicating a multiple of 1.25 gallons of water and the number preceding the “C” indicating the size in square feet that can be extinguished. These are the least expensive types of fire extinguisher.

Halon (classes B:C) extinguishers contained a gaseous agent that interrupts the chemical process of combustion by obstructing the flames’ access to oxygen and cooling the fire’s combustible material. They are primarily used in medical centers and were once the most common fire extinguishers sold. Halon was banned from new production in 1994, as it contributes to ozone depletion and has a long atmospheric lifetime of 400 years or more. It is still used to refill older extinguishers, but it is no longer available as a new product.

Graphite-based (G-Plus, G-1, Lith-X, or Chubb Pyromet) fire extinguishers contain dry graphite that smothers metal fires, such as magnesium. It can also be used on hot burning copper or other metals, but is not effective against flowing or vertical metal fires.